How to Identify Damselfish

To identify Damselfish (Chromis chromis), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Adults are typically dark brown to bluish-black, sometimes with a purplish sheen, especially when observed in deeper waters or during breeding. Juveniles are often iridescent blue with bright blue spots, gradually darkening with age. The fins are generally the same color as the body, though the caudal fin can appear slightly darker.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Deeply forked caudal fin, Small, terminal mouth, Relatively large eyes, Laterally compressed body

Dorsal fin

Single dorsal fin with 13-14 spines and 10-12 soft rays. The spiny portion is longer than the soft-rayed portion.

Tail fin

Deeply forked caudal fin, with pointed lobes.

Pectoral fin

Well-developed pectoral fins, typically clear or slightly dusky.

Distinctive fins

Anal fin with 2 spines and 9-11 soft rays. Pelvic fins are thoracic.

Identification Tips

1. 1

   Coloration

   Adults are uniformly dark brown to bluish-black. Juveniles are bright iridescent blue with small blue spots, a key identifier for younger individuals.

2. 2

   Caudal Fin

   The deeply forked caudal fin is a prominent feature, distinguishing it from many other small reef fish.

3. 3

   Schooling Behavior

   Often observed in large, active schools, particularly in mid-water over rocky reefs.

4. 4

   Size

   Reaches a maximum total length of about 16 cm (6.3 inches), but commonly observed around 10-12 cm (4-5 inches).

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